2-Ethylhexyl Diphenyl Phosphate Exposure Induces Duodenal Inflammatory Injury Through Oxidative Stress In Chickens

2-Ethylhexyl Diphenyl Phosphate(EHDPHP)is a widely used organophosphorus flame retardant and plasticizers.With the growth of China’s industrialization level,the production and usage of EHDPHP are increasing year by year.Cause to be prevalent in the environment.EHDPHP is metabolically toxic and can cause a certain degree of damage to organisms when ingested in a certain amount.Chickens are widely raised economic animals.In the breeding environment,EHDPHP is widely present in the feed,drinking water,air and other environment of chicks,which is easy to be ingested and has adverse effects on the growth of chicks.To explore the mechanism of EHDPHP damage to the duodenum of chicks,a subacute toxicity model of EHDPHP was established,and the effects of EHDPHP on the growth and development of chicks and duodenal tissue damage were observed by continuous gavage.Ninety one-day-old healthy Hy-line white-feather male chickens were randomly divided into C1(blank control group),C2(vehicle control group),L(800 mg/kg),M(1600 mg/kg)and H(3200 mg/kg)after one week of environmental adjustment.The clinical symptoms of the chicks were observed at 14 d,28 d and 42 d,respectively.After the chicks were euthanized,the duodenal tissue samples of the chicks were collected and H.E.The histopathological changes were observed under a light microscope.ELISA kits were used to detect tissue immune factors(s Ig A,s Ig M)and P-glycoprotein(P-gp).Oxidative damage indicators,reactive oxygen species(ROS),glutamylcysteine ligase(GCLC,GCLM),malondialdehyde(MDA),superoxide dismutase(SOD),glutathione peroxidase(GSH-Px)activity content;q RT-PCR and Western Blot were used to detect mucosal proteins(CLDN,OCCLUDIN,ZO-1,JAM)and oxidative and antioxidant markers(HO-1,NQO1,GCLC,GCLM).The expression levels of inflammatory proteins(NF-κB,COX2).The results showed that continuous exposure to EHDPHP significantly inhibited the growth and development of chicks,and the inhibitory effect increased significantly with the increase of time and dose.Under the light microscope,the duodenal villi of chicks showed different degrees of rupture,the mucosal layer showed different degrees of inflammatory cell infiltration,and some blood vessels were ruptured in the plasmacytomous layer,and the blood cells were dispersed.On the 42 nd day,the duodenal plasmacytomous layer of chicks in the EHDPHP exposure group showed obvious hyperemia and bleeding.In the detection of tissue oxidative factors,it was found that EHDPHP caused an imbalance between oxidation and antioxidation in the duodenum of chicks,as indicated by the increased levels of reactive oxygen species(ROS),malondialdehyde(MDA),and the expression of glutamylcysteine ligase(GCLC,GCLM)and quinine NADH dehydrogenase 1(NQO1)in tissues(P<0.05).The contents of superoxide dismutase(SOD),glutathione peroxidase(GSH-Px)and heme oxygenase(HO-1)were significantly decreased(P<0.05).The results of tissue inflammatory protein detection showed that continuous exposure to EHDPHP caused intestinal inflammation,especially the up-regulation of inflammatory protein(NF-κB,COX2)expression in tissues(P<0.05).In the detection of mucosal structure and immune barrier proteins,it was found that continuous exposure to EHDPHP caused a decrease in the expression of immune factors(s Ig A,s Ig M)and P-glycoprotein(P-gp)in duodenal mucosa of young chickens(P<0.05).At the same time,the expression of CLDN,OCCLUDIN,ZO-1 and JAM in duodenal mucosa was decreased(P<0.05),and the above showed a trend of aggravation with the increase of exposure time and concentration of EHDPHP.In summary,EHDPHP can cause oxidative stress in the duodenum of chicks,leading to intestinal inflammation,destroying the intestinal mucosal structure and mucosal immune barrier,and inhibiting the normal growth of chicks.